<PackageReference Include="System.Configuration.ConfigurationManager" Version="8.0.0-rc.1.23419.4" />

IInternalConfigSystem

public interface IInternalConfigSystem
Defines an interface used by .NET to initialize application configuration properties.
namespace System.Configuration.Internal { public interface IInternalConfigSystem { bool SupportsUserConfig { get; } object GetSection(string configKey); void RefreshConfig(string sectionName); } }